The United States presently consumes about 42 billion gallons per year of diesel for transportation. In 2007, a nascent biodiesel industry produced 250 million gallons of a bio-derived diesel substitute produced from mostly soybean oil in the U.S. Biodiesel are fatty acid methyl esters (FAME) made typically by the base-catalyzed transesterification of triglycerides, such as vegetable oil and animal fats. Although similar to petroleum diesel in many physicochemical properties, biodiesel is chemically different and can be used alone (B100) or may be blended with petrodiesel at various concentrations in most modern diesel engines. However, a practical and affordable feedstock for use in biodiesel has yet to be developed that would allow significant displacement of petrodiesel. For example, the price of soybean oil has risen significantly in response to the added demand from the biodiesel industry, thus limiting the growth of the biodiesel industry to less than 1% of the diesel demand.
It has been proposed to use algae as a feedstock for producing biofuel, such as biodiesel. Some algae strains can produce up to 50% of their dried body weight in triglyceride oils. Algae do not need arable land, and can be grown with impaired water, neither of which competes with terrestrial food crops. Moreover, the oil production per acre can be nearly 40 times that of a terrestrial crop, such as soybeans. Although the development of algae presents a feasible option for biofuel production, there is a need to reduce the cost of producing the biofuel from algae. The fall in oil price in late 2008 places an even greater pressure on the fledgling biofuel industry to develop inexpensive and efficient processes. Provided herein is a cost-efficient approach for growing algae in a large scale for production of biofuel.